AppMaps and CallApps are two pieces of your inbound call path that work together to get callers to the correct destination.
AppMaps consist of one or more match expressions, each of which has a regular expression and CallApp ID attribute. When an inbound call reaches one of your Gateways, the dialed number is compared against the AppMap's match expressions in order until a match is found. Once a match has been found, the call is processed according to the associated CallApp.
Many businesses will have only one CallApp, especially if they have only one phone number. But if you have more than one phone number, the AppMap allows you to treat calls differently depending on how they reached you.
During the Quickstart wizard, a default AppMap was added to your Gateway with a match expression of
This expression matches all calls, and ensures they will be handled by the Gateway's default CallApp. It is recommended to keep a catch-all line like this one at the end of your AppMap to ensure that any calls which aren't matched by earlier lines still have a destination.
A CallApp is just a set of instructions for where to send a call. For example you can send the call to one or more Endpoints, or forward it to another phone number. The AppMap decides which CallApp to use, and the CallApp decides what happens to a call.